Is that Santa's sleigh pulled by a magical herd of reindeer?
A bright streak of light in the pre-dawn skies above the U.K. tomorrow morning (Dec. 24) could easily be mistaken for Santa Claus getting an early start to his Christmas deliveries — but the glowing trail of light actually belongs to the International Space Station (ISS) making one of its routine laps of Earth. The ISS will also be visible early on Christmas morning, coinciding with Santa's journey back to the North Pole.
Weather permitting, the space station will be visible under clear skies for about six minutes, starting at 6:54 a.m. GMT. It will appear 16° above the western horizon, and travel across the sky at a maximum height of 82° above the horizon before disappearing 10° above the eastern horizon, which should make it visible in many parts of the UK, according to NASA's Spot the Station page. The ISS will be visible again on Dec. 25, at 6:06 a.m. GMT, for about four minutes. It will follow a similar trajectory as the previous day, appearing 57° above the western horizon, and traveling across the sky at a maximum height of 89° above the horizon before disappearing 10° above the eastern horizon.
Related: 10 Christmas space facts to get you into the festive spirit
The ISS is visible to the naked eye as it orbits the Earth at around 250 miles (400 kilometers). It travels at a speed of about 17,500 miles per hour (28,000 kilometers per hour) so that as it passes overhead, it often appears as a bright moving star, unmistakable against the backdrop of the early morning sky. And, coinciding with the holiday, the space station could easily double as Santa's sleigh to innocent eyes.
To see the space station pass overhead, it's recommended that viewers find a clear, unobstructed spot with as little light pollution as possible. A telescope or binoculars are not necessary, as the ISS will be visible as a bright light moving steadily across the sky to the naked eye. In fact, the space station is typically the brightest object in the sky (except for the moon). The light we see from Earth is actually sunlight reflected off the solar panels on the side of the orbiting lab.
The ISS orbits Earth once every 90 minutes, which means it circles the planet 16 times each day. While Dec. 24 offers an optimal time to see the space station in the early morning and soak in the wonder and magic of Santa leading up to Christmas, there will be other opportunities to catch the orbiting lab as it passes overhead. NASA's Spot the Station page can help viewers determine when the ISS can be seen from anywhere around the world.
For the astronauts aboard the space station, the holidays are celebrated in a uniquely special way, with festive meals, decorations and even video calls to loved ones back on Earth.
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